Stand mixers are well known and versatile kitchen appliances which generally (though not necessarily) comprise a somewhat C-shaped casing, including a support for a bowl in which ingredients are to be mixed, an upright section and a header portion which is supported by the upright section so as to dispose, overhead of the bowl, a socket housing a drive outlet capable of imparting rotational drive to a shaft inserted into the socket and coupled to the drive outlet. The drive outlet socket faces down towards the bowl and can accommodate, by temporary insertion thereinto, shafts of various tools designed to couple to the drive outlet and devised for such purposes as whisking, blending, kneading and beating ingredients. The drive outlet is configured to impart a planetary drive motion to tools attached thereto; whereby a tool is rotated about an axis and also processes around a circular path centered on the axis.
The beater tool is particularly useful, as it can perform a number of tasks, and such tools have evolved into a format whereby a pair of substantially rigid arm members, shaped to substantially conform to the profile of the inner upright surface and a portion of the base of the mixing bowl, are formed into a rigid frame structure by joining together their lower parts and providing a transversely-extending upper support, linking the upper parts of the arm members and supporting at its centre an upwardly-directed drive shaft, or a receptor for such a shaft; the shaft being in any event intended for insertion into the drive socket to couple with the drive outlet.
Such beater tools work reasonably well in general use. However, production tolerances make it difficult to ensure that the arm members of the beater accurately match the inner surface of the bowl. Accordingly, particularly when material of a clingy nature is being mixed, a problem can arise in that there is a tendency for some of the material to adhere to the surface of the bowl so that it is not thoroughly incorporated into the mixture being made.
GB 483,800 disclosed, as long ago as 1938, that this problem could be addressed by providing the arm members of the beater with flexible scraping members capable of adapting themselves to fully conform to the bowl surface, and thus provide a complete and systematic scraping or wiping action in order to remove adhering material from the surface of the bowl and redirect it back into the mixture. This “flexi-beater” concept has been revisited in recent years, as described for example in U.S. Pat. No. 7,314,308 to Fallowes et al, WO 2007/007202 to Kaas and WO 2006/083560 to Busick, but practical problems still exist in relation to fitting the scraping members to the arm members whilst allowing for cleaning, economical replacement of worn or damaged scraping members and/or the use of exchangeable scraping members with different operating characteristics, and it is an aim of this invention to address one or more of these problems.